model = self.SimpleModel()

    saved_model_save.save(model, self._input_saved_model_path)

    # Set an invalid value of -1 to QuantizationMethod.preset_method.
    options = quant_opts_pb2.QuantizationOptions(
        quantization_method=quant_opts_pb2.QuantizationMethod(preset_method=-1)
    )

    with self.assertRaises(ValueError):
      quantize_model.quantize(